The present invention relates to an improved oxygen absorber for absorbing oxygen primarily in ambient temperature dry environments and which will also function satisfactorily in in both low temperature environments and in moist environments.
By way of background, particulate iron is known as an oxygen absorber because it readily combines with oxygen. In the past, various types of particulate iron have been used, including hydrogen reduced iron, electrolytically reduced iron, atomized iron, and milled pulverized iron. However, the hydrogen reduced iron, the atomized iron and the milled pulverized iron absorb oxygen relatively slowly. The electrolytically reduced iron absorbs oxygen faster, but at lower temperatures at which foods are normally refrigerated it absorbs oxygen at a slower rate than desired to remove the oxygen before the initial stages of food spoilage commence. Furthermore, in dry environments it is necessary to supply moisture for producing an electrolytic action which is necessary for activating the oxygen-absorbing action of the iron. However, silica gel which has been used in the past for adsorbing moisture from a moist environment cannot be used for a plurality of reasons. The first reason is that if it contains sufficient moisture to supply such moisture, it is not flowable and thus cannot be used efficiently in a manufacturing process. The second reason is that if it contains a lesser amount of moisture so that it remains flowable, it will not give this moisture up for combining with a salt to produce an electrolyte, and further, in a dry environment it will not have a source of moisture from which it can adsorb the necessary moisture for activating oxygen absorption. Furthermore, the envelopes of certain prior oxygen-absorbing packets were deficient for use in dry environments in that they permitted moisture to escape from a moisture-containing oxygen-absorbing composition which diminished the moisture available for producing the required electrolytic action.
It is the primary object of the present invention to provide an improved oxygen-absorbing composition which can supply moisture in dry environments for the purpose of enhancing oxygen absorption.
Another object of the present invention is to provide an improved oxygen absorber which is flowable and which contains activated carbon with a relatively high percentage of water impregnated therein which is required to supply moisture for absorbing oxygen in dry environments, the flowability being required for efficient handling in the manufacturing process.
A further object of the present invention is to provide an improved oxygen-absorbing composition which includes particulate annealed electrolytically reduced iron and moisture-impregnated activated carbon which will provide good oxygen absorption in dry environments, in moist environments and in low temperature environments.
Yet another object of the present invention is to provide an improved combination of a package and an oxygen-absorbing composition which will provide good oxygen absorption in dry environments.
A still further object of the present invention is to provide an improved combination of a package and an oxygen-absorbing composition which inhibits migration of water from a moisture-carrying product in the package and thus conserves available moisture for creating an electrolyte for combining with iron to effect oxygen-absorption in dry environments. Other objects and attendant advantages of the present invention will readily be perceived hereafter.
The present invention relates to an oxygen-absorbing composition comprising in relatively sufficient proportions particulate annealed electrolytically reduced iron, salt for combining with water to produce an electrolyte which combines with said iron to cause it to absorb oxygen, and a water-supplying component comprising activated carbon with liquid water therein for supplying said water to said salt to produce said electrolyte.
The present invention also relates to an oxygen-absorbing packet for absorbing oxygen in dry environments comprising the above composition in an envelope consisting of a laminate of ethylene vinyl acetate, water and grease resistant paper, and microperforated polyester film.
The various aspects of the present invention will be more fully understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein: